The automatic door locks on my pickup have stopped working. At 1st, I was having problems with the nsbu switch so I changed it and everything was working fine. Then the auto door locks started acting up. I am unable to lock or unlock the doors with either the driver side or passenger side door switch. I also cannot lock or unlock them using the keyless entry. The lights and horn flash and honk when you try to use the key fob but the door locks don't function. I can hear the relay in the fuseblock engaging when I press the door lock switch on the driver side door.
Also, when I press the lock button on the doors and then open the rear door, the horn starts honking ( anti theft).
Do you have any suggestions as to where I need to start looking to get the door locks to work?
One other thing: I swapped the nsbu switch on my pickup to my brother's and everything worked fine on his but still did not work on mine.
Thanks in advance for any help.

Check your mir/lock 3amp fuse and dr lock fuse 20amp both located in the fuse block on the left side of the dash.

Thanks for replying. I checked all of the fuses and the relays in the driver's side fuse block but still no luck. can you give me some more ideas where to look? All help is appreciated. This has benn going on for a couple of weeks now.

I will have to try later, the board is actimg stupid and wont let me post the diag chart

I should add that it was intermittent at first. Sometimes they worked and sometimes they didn't. Now they have gotten where they don't work at all.